Fundamentals
What physical thing moves in a circuit?
Electron
What unit is used to measure electric power?
Watt
What is resistance?
the opposition to the flow of electric current?
In a parallel circuit, how are the components connected?
In a series circuit, how many current paths are there?
1
What term is used for the rate at which charge flows through a conductor?
Electric current
A 6.0 V battery creates 0.50 A current. What is the power?
3.0W
What is Ohm's Law?
V=IR or R=V/I
In a parallel circuit, how does the voltage across each branch compare?
V_{eq} = V_1 = V_2 =V_3 \cdots
How does current change in a series circuit as it moves through the devices?
It doesn't! It is the same throughout
What must a circuit have for it to be considered a simple circuit and not dangerous?
1. Power supply
2. Conducting wires
3. A Device (to take the energy)
4. A closed conducting path
How much Energy does a 2000watt blender use if it's on for 10min? (Energy = kWh)
0.33kWh
How can you calculate the total resistance in a parallel circuit?
First find the current in each branch, add them to find the total current in the circuit, then use Ohm's Law with the Total Current and Total Voltage to solve for Total Resistance.
How can you tell car headlights are wired in parallel?
they remain lit even if one bulb fails
What happens when one bulb burns out in a series circuit?
The circuit breaks
What are the variables and units for Voltage, Current, and Resistance?
Voltage - V measured in volts (V)
Current - I measured in amps (A)
Resistance - R measured in Ohms (Ω)
What is the cost to run a 1400watt device for 3 entire days at a rate of $0.13 per kWh?
$13.10
Name all 3 factors in what gives a wire more resistance? (think physically)
1. Longer wire
2. Less width, skinnier wire
3. Material
Calculate the current through each bulb in the parallel circuit on the board and say what bulb would be brightest. Explain why.
Must have the correct currents and bulb with a correct explanation. The brightest bulb should have the highest current and they all receive the same voltage.
What is the voltage across a battery if the current going through two identical 5-ohm resistors in series is 2 A?
20V
Describe how a battery provides energy to devices. (be specific about where the battery itself gets energy from)
The chemical reaction sorts the negative and positive charge within the battery creating electric potential energy. The circuit, filled with conductors and devices, allow for the built up energy and the electrons to travel around and through said devices. When the electrons, filled with energy pass through these devices, there is a voltage drop and an energy conversion depending on the type of device. The electron returns back to the battery with no energy only to be lifted up and through the chemical reaction again.
What is the cost to run a 2500watt hairdryer for 10mins a day for an entire year at a rate of $0.19 per kWh?
$28.90
What happens to the total resistance in a series and a parallel circuit if a resistor is added to the circuit. Explain why in each answer. (2 answers)
In series the total resistance goes up if you add a resistor because the current has to flow through an additional resistor.
In parallel the total resistance would decrease because although you are adding a resistor, it is opening up a new path for the current to flow. More paths, more options, less resistance for the electrons.
Calculate the total Resistance in a Parallel Circuit with a 12V battery with 3 resistors in parallel, 1Ω, 2Ω, and a 5Ω.
The current in each branch is 12A, 6A, and 2.4A. Total Current is 20.4A.
Total Resistance is 0.59Ω
Calculate the Voltage drop across each bulb in a series circuit with a 6V battery, a 2Ω, 4Ω, and 3Ω bulbs.
Total current is 0.67A
1.33V
2.66V
2.01V